An Introduction to Check Constraints

Check constraints are a great way to enforce additional logic at the row level, perhaps making sure that a gender column only includes the values M or F. The constraint can reference multiple columns, but only within the same row, and you have the option to NOT enforce it against existing data. A useful technique to know!

Andy Warren is a software trainer focusing on SQL Server, a member of the PASS Board of Directors, and a principal in this site - SQLShare.com.

ricardoacaraujo@hotmail.com on 4/26/2010

Bom

Mark Hions on 4/26/2010

Isn't the default name of a constraint something system generated, with trailing digits and multiple underbars?

Gary Williams on 4/26/2010

Very Informative, Short but precise

concoran on 4/26/2010

Excellante!

A Alagu Ganesh on 4/26/2010

good

Charlie Bruno on 4/27/2010

One item is that the fonts in the images and displays are too small for me to see. Other than that, excellent basic training video.

FELIX on 4/27/2010

Very informative!

David Kats on 4/29/2010

Andy - Great video - But you did not show how to avoid use constrain against existing data in the table

Leonard Peoples on 4/29/2010

Very useful. I'll definitely start using this feature

Jonathan Winer on 5/3/2010

It would be interesting to hear a brief discussion on how check constraints may affect performance, much like a trigger might.

Steve Culshaw on 5/29/2010

Good overview

Tim Bochard on 6/29/2010

Great video and sound quality. Well explained -- kept a simple topic simple.

Sophia Ferguson on 3/16/2011

great work